his project takes 24VDC in, and outputs 12V for LEDs, and 5V for a Raspberry Pi. TI has a neat tool where you can enter the requirements for a power supply, and it spits out a proper circuit. Here's what it did for me:
That's an LM25011 for the 12V supplying 2A, and an LMR14050 for 5V supplying 2A.
Dead simple, all you have to do is lay it out on a board.
This board also has six outputs for two RGB LED strips on the PWM outputs of the Pi. These outputs use a NTD4906N power MOSFET:
What does the board look like?
No it's not perfect, but it will work, and I like putting instructions and unicorns on the silkscreen.
Since you're designing a board why not add a LiPo battery backup to the 5V supply? You could ensure a smooth shutdown of the Raspi and prevent SD card corruption.